/*

 * Copyright (c) 2016, 2019, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

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 */

#ifndef SHARE_JFR_RECORDER_CHECKPOINT_TYPES_TRACEID_JFRTRACEIDEPOCH_HPP

#define SHARE_JFR_RECORDER_CHECKPOINT_TYPES_TRACEID_JFRTRACEIDEPOCH_HPP

#include "memory/allocation.hpp"

#define USED_BIT 1

#define METHOD_USED_BIT (USED_BIT << 2)

#define EPOCH_1_SHIFT 0

#define EPOCH_2_SHIFT 1

#define USED_EPOCH_1_BIT (USED_BIT << EPOCH_1_SHIFT)

#define USED_EPOCH_2_BIT (USED_BIT << EPOCH_2_SHIFT)

#define METHOD_USED_EPOCH_1_BIT (METHOD_USED_BIT << EPOCH_1_SHIFT)

#define METHOD_USED_EPOCH_2_BIT (METHOD_USED_BIT << EPOCH_2_SHIFT)

#define METHOD_AND_CLASS_IN_USE_BITS (METHOD_USED_BIT | USED_BIT)

#define METHOD_AND_CLASS_IN_USE_EPOCH_1_BITS (METHOD_AND_CLASS_IN_USE_BITS << EPOCH_1_SHIFT)

#define METHOD_AND_CLASS_IN_USE_EPOCH_2_BITS (METHOD_AND_CLASS_IN_USE_BITS << EPOCH_2_SHIFT)

class JfrTraceIdEpoch : AllStatic {

  friend class JfrCheckpointManager;

 private:

  static bool _epoch_state;

  static void shift_epoch();

 public:

  static bool epoch() {

    return _epoch_state;

  }

  static jlong epoch_address() {

    return (jlong)&_epoch_state;

  }

  static u1 current() {

    return _epoch_state ? (u1)1 : (u1)0;

  }

  static u1 previous() {

    return _epoch_state ? (u1)0 : (u1)1;

  }

  static traceid in_use_this_epoch_bit() {

    return _epoch_state ? USED_EPOCH_2_BIT : USED_EPOCH_1_BIT;

  }

  static traceid in_use_prev_epoch_bit() {

    return _epoch_state ? USED_EPOCH_1_BIT : USED_EPOCH_2_BIT;

  }

  static traceid method_in_use_this_epoch_bit() {

    return _epoch_state ? METHOD_USED_EPOCH_2_BIT : METHOD_USED_EPOCH_1_BIT;

  }

  static traceid method_in_use_prev_epoch_bit() {

    return _epoch_state ? METHOD_USED_EPOCH_1_BIT : METHOD_USED_EPOCH_2_BIT;

  }

  static traceid method_and_class_in_use_this_epoch_bits() {

    return _epoch_state ? METHOD_AND_CLASS_IN_USE_EPOCH_2_BITS : METHOD_AND_CLASS_IN_USE_EPOCH_1_BITS;

  }

  static traceid method_and_class_in_use_prev_epoch_bits() {

    return _epoch_state ? METHOD_AND_CLASS_IN_USE_EPOCH_1_BITS :  METHOD_AND_CLASS_IN_USE_EPOCH_2_BITS;

  }

};

#endif // SHARE_JFR_RECORDER_CHECKPOINT_TYPES_TRACEID_JFRTRACEIDEPOCH_HPP